Flow boundary condition modeling

You define a Flow Boundary Condition simulation object on a polygon face, which:

• Must be generated before the 3D flow mesh.

• Does not need to be meshed for body-fitted fluid meshing and for a flow-only solution.

• Must be co-planar with the faces of the 3D fluid elements directly affected by the Flow Boundary Condition for body-fitted fluid meshing or completely immersed for immersed boundary method.

• Must form part of the exterior boundary of the flow domain, for all types except Internal Fan. Internal faces are embedded in the fluid domain.

• Must be created and constrained carefully since it defines the location and extent of the Flow Boundary Condition opening.

• Is fully associative with the Flow Boundary Condition. If the dimensions of the face change, the software automatically modifies the Flow Boundary Condition.

Checking the mesh density across openings

The density of the 3D flow mesh adjoining a Flow Boundary Condition is important. The flow solver needs at least two fluid elements or cells across any opening.

Avoiding non-physical models

You should avoid defining non-physical models when you create a Flow Boundary Condition. The most common mistakes include:

• Defining an Inlet Flow or Outlet Flow type, but no corresponding Opening or Static Pressure type Flow Boundary Condition.

• Defining a Flow Boundary Condition with an extremely high velocity or flow rate (for example, above Mach 4 for air).

In both of these cases, the solution may not converge.

How do I

Create a Flow Boundary Condition

Learn more

Flow Boundary Condition types

Modeling fan swirl

Working with fan curves

Modeling heat loss or gain in a recirculation loop

External Conditions

Fan Speed Controller

Inputs to expressions

Fluid meshing

Immersed boundary meshing

Look up more details

Auto-generated expressions

Geometry creation for body-fitted fluid meshing

Geometry preparation for immersed boundary method

Quick links

Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal boundary conditions

Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Flow boundary condition modeling, Simcenter 3D 2021.1 Series

© 2020 Siemens

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

MathJax.Hub.Config({ TeX: { extensions: ["autoload-all.js"] }, tex2jax: { displayMath: [ ] }, "SVG": { scale: 125 } });